Primary or secondary OH groups can be protected as 2-naphthylmethyl (NAP) ethers, e.g. with NaH in DMF. The NAP ether is stable to dilute aqueous HCl or NaOH, but is cleanly hydrogenolyzed with Pd/C; preferential cleavage in the presence of a benzyl ether can be achieved in high yield: J. Org. Chem., 63, 4172 (1998). NAP protection has been utilized in carbohydrate synthesis where stability to 4% TFA in CHCl3, hot 80% AcOH, SnCl2/AgOTf, or HCl/EtOH were demonstrated, conditions under which the 4-methoxybenzyl (PMB) group is cleaved; both NAP and PMB groups are efficiently cleaved with DDQ: Tetrahedron Lett., 41, 169 (2000). NAP protection of amino groups and other N functions has also been reported. Cleavage was effected under mild condtions with DDQ: Synlett, 2065 (2003).
